To design a transceiver for broadband digital wireless communications, accurate modeling of a channel, i.e., a communication path is required. Channel modeling is a process that defines information of channel distortion as a specific structure, which occurs multipath propagation in a wireless data transmission process, and obtains variables of the specific structure.
Examples of a channel sounding device for broadband channel modeling include a sounding device using a basic M-sequence, and a sounding apparatus using an orthogonal frequency division multiplexing (OFDM) symbol using a multi-carrier.
The sounding apparatus using the M-sequence has a wide operating range and implements a simple modeling method, but has limitations in that signal loss occurs because of an unlimited channel bandwidth and high signal power in a channel area excluding a bandwidth of a channel of interest (COI).
In contrast, the sounding device using the OFDM symbol has limitations in that unless a high-performance analog device is used for an amplifier, an analog-to-digital (AD) and digital-to-analog (DA) converter and a reception signal synchronizer, distortion of the device occurs, making it difficult to perform accurate channel modeling and reducing its operating range.
Also, in the case of high-speed broadband mobile communications, high-order quadrature amplitude modulation (QAM) signal of 32-QAM or higher must be used. Thus, receiver performance may be significantly deteriorated by an influence of signal noise, channel distortion, carrier synchronization, etc.
To overcome the limitations, a high-performance analog device may be employed and/or a complicated compensation algorithm for distortion processing of the device may be used. However, this may complicate the structure of the sounding device and increases a cost.
The digital modem technique employing the multi-carrier method, such as the OFDM, has limitations of a complicated synchronization technique at a reception terminal for precise signal synchronization, an expensive linear amplifier, and an expensive AD/DA converter with high resolution. However, a digital modem technique using a single carrier method can easily implement a low-power/low-priced receiver with a simple structure, using a simple synchronization technique at a reception terminal, a low-priced amplifier and an AD/DA converter with low resolution.
However, most of current devices for channel modeling for broadband mobile communications use an OFDM signal, and there is almost no device for modeling a mobile environment channel by the single carrier method for broadband mobile communications.
Although interference of an adjacent channel is a very important issue in channel modeling of the wireless communication field using multiple channels, a related art channel modeling device uses a separate device to analyze the adjacent channel interference, which lowers efficiency of channel modeling.